I've found a solution of sorts: I put up with having to re-establish connection each session and I use Firefox and Thunderbird instead of Safari & Mail!!
I have just used the auto-update function on my dual-usb iBook G3 to install the most recent security update (I'm using a fully updated version of Panther).
Since updating there are a number of problems:
Safari and Mail programs hang (with the spinning beach-ball).
Airport contact with...